The midpiece consisted of the centriolar complex and the sleeve. 中段包括中心粒复合体和袖套。
As spermatozoa progress through the epididymis they first acquire the capacity to phosphorylate tyrosine on targets on the principal piece, followed by the midpiece. 精子进入附睾后,它首先获得将精子主段以及中段上的目的蛋白的酪氨酸磷酸化的能力。